Roadside Revegetation

IMPLEMENTATION GUIDES
A
B
Figure 10-123 | Pot planter
The pot planter creates a planting hole by
injecting high pressure water into the soil
(A). Once the soil is liquefied, the container
is pushed into the soil to the appropriate
depth (B).
soil (Figure 10-123A). The pot planter has 3-inch vanes attached to the sides of the nozzle,
which create holes large enough for containers up to one gallon (Figure 10-123B). The hole
that is created by the pot planter is actually a soil slurry that is displaced when the root plug
is pushed into it at the desired planting depth. Once the water drains from the slurry into the
surrounding soil, the soil settles in around the root plug, assuring good soil-to-root contact.
The advantages of using a pot planter include (1) container plugs are thoroughly moistened
at outplanting, (2) there are fewer air pockets in the soil and better root-to-soil contact, and (3)
soil around the planting hole is moistened, allowing roots more time to move out of the plug
and into the native soil. These advantages create the opportunity for earlier fall planting dates,
even as early as late August to early September in some areas. The earlier the fall planting, the
greater the chance for rooting to occur before winter sets in. This rooting will be in addition
to the root growth that occurs the following spring and can make the difference in whether
a seedling survives the first growing season. Large containers can be planted quickly at a rate
of approximately one plant per minute (Hoag 2006). The pot planter is limited by the same
factors as the waterjet stinger, which include steep slope gradients, inaccessibility, high soil
rock content, and poor water source availability.
Planting into Engineered Structures – There are occasions when seedlings will be planted
as engineered structures are being built. These structures include vegetated gabion walls,
riprap, and retaining walls (see Inset 10-22). Planting must be well planned and integrated into
the construction schedule. Since road construction often takes place in the summer when
plants are in full growth, special handling methods and irrigation must be implemented
during installation to assure optimum seedling establishment (Figure 10-124). Installing plants
into riprap, for example, requires good planning and integration into construction activities.
Drawings and a set of planting instructions are essential. Seedlings are partially planted in the
existing soil and partially in riprap. Riprap and soil is hand placed around the seedling plug to
assure good root–to-soil contact and that the seedlings are handled with care. The remainder
of the riprap is placed and the seedlings are irrigated. Each vegetated engineered structure
will require different sets of instructions and drawings that are specific to the objectives and
environmental conditions of the site.
Figure 10-124 | Plants integrated
with engineered structures
Engineered structures of gabions and
riprap require tall nursery stock and
special installation techniques. When
properly done, however, plants survive
and grow well and greatly increase the
visual appearance of the structure.
Roadside Revegetation: An Integrated Approach to Establishing Native Plants and Pollinator Habitat
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